CVE-2026-55655

MEDIUMPre-NVD 5.05.0—
EchelonGraph scoreHIGH confidence

Score 5.0 from GitHub Security Advisory published 2026-06-23. the CNA's CVSS baseline 5.0; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cna:redhat, epss, ghsa
Trending — 4 sources updated this week
5.0
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 5.0Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

A flaw was found in OpenSSH. A local unprivileged attacker on a Linux client host can hijack client-side X11 forwarding connections. This is possible by pre-binding the preferred abstract X socket name when X11 forwarding is enabled and a local UNIX-domain X socket is used. A successful attack can compromise the confidentiality of forwarded X11 traffic, including sensitive window contents and input, and may allow some manipulation of the forwarded session.

CVSS v3
5.0
EG Score
5.0(high)
EPSS
0.3%
KEV
Not listed

Published

June 23, 2026

Last Modified

June 30, 2026

Advisory Details (2)

Auto-updated Jun 23, 2026
Patch available. Sources: redhat.
redhat

2462250 – (CVE-2026-55655) CVE-2026-55655 openssh: Local MITM of X11 forwarding via abstract UNIX socket pre-binding in Red Hat Enterprise Linux OpenSSH client versions

https://bugzilla.redhat.com/show_bug.cgi?id=2462250
redhat Patch Available

cve-details

https://access.redhat.com/security/cve/CVE-2026-55655

Vendor Advisories for CVE-2026-55655(2)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 20× in last 7d / 46× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-06 19:11 UTCEG score recompute
  2. 2026-07-06 19:11 UTCGHSA enrichment
  3. 2026-07-06 16:27 UTCEPSS rescore
  4. 2026-07-06 16:27 UTCEPSS rescore
  5. 2026-07-05 19:49 UTCEG score recompute
  6. 2026-07-05 19:49 UTCGHSA enrichment
  7. 2026-07-04 20:27 UTCEG score recompute
  8. 2026-07-04 20:27 UTCGHSA enrichment
  9. 2026-07-04 06:31 UTCEPSS rescore
  10. 2026-07-04 06:31 UTCEPSS rescore
  11. 2026-07-03 22:01 UTCMITRE cvelistV5CVSS v3 → 5
  12. 2026-07-03 21:05 UTCEG score recompute
  13. 2026-07-03 21:05 UTCGHSA enrichment
  14. 2026-07-02 21:43 UTCEG score recompute
  15. 2026-07-02 21:43 UTCGHSA enrichment
  16. 2026-07-01 22:22 UTCEG score recompute
  17. 2026-07-01 22:21 UTCGHSA enrichment
  18. 2026-07-01 15:07 UTCEPSS rescore
  19. 2026-06-30 22:45 UTCEG score recompute
  20. 2026-06-30 22:45 UTCGHSA enrichment
  21. 2026-06-29 23:23 UTCEG score recompute
  22. 2026-06-29 23:23 UTCGHSA enrichment
  23. 2026-06-29 14:06 UTCEPSS rescore
  24. 2026-06-29 14:06 UTCEPSS rescore
  25. 2026-06-29 00:02 UTCEG score recompute
Show 21 more
  1. 2026-06-29 00:02 UTCGHSA enrichment
  2. 2026-06-28 14:07 UTCEPSS rescore
  3. 2026-06-28 04:56 UTCEPSS rescore
  4. 2026-06-28 04:56 UTCEPSS rescore
  5. 2026-06-28 00:40 UTCEG score recompute
  6. 2026-06-28 00:39 UTCGHSA enrichment
  7. 2026-06-27 03:08 UTCEPSS rescore
  8. 2026-06-27 01:16 UTCEG score recompute
  9. 2026-06-27 01:16 UTCGHSA enrichment
  10. 2026-06-26 01:55 UTCEG score recompute
  11. 2026-06-26 01:55 UTCGHSA enrichment
  12. 2026-06-25 17:48 UTCNVD updateCVSS v3 → 6.1
  13. 2026-06-25 02:33 UTCEG score recompute
  14. 2026-06-25 02:32 UTCGHSA enrichment
  15. 2026-06-24 14:05 UTCEPSS rescore
  16. 2026-06-24 03:10 UTCEG score recompute
  17. 2026-06-24 03:10 UTCGHSA enrichment
  18. 2026-06-23 21:33 UTCEPSS rescore
  19. 2026-06-23 21:33 UTCEPSS rescore
  20. 2026-06-23 03:46 UTCEG score recompute
  21. 2026-06-23 03:45 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-55655?
CVE-2026-55655 is a medium vulnerability published on June 23, 2026. A flaw was found in OpenSSH. A local unprivileged attacker on a Linux client host can hijack client-side X11 forwarding connections. This is possible by pre-binding the preferred abstract X socket name when X11 forwarding is enabled and a local UNIX-domain X socket is used. A successful attack can…
When was CVE-2026-55655 disclosed?
CVE-2026-55655 was first published in the National Vulnerability Database on June 23, 2026, with the most recent update on June 30, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-55655 actively exploited?
CVE-2026-55655 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-55655?
CVE-2026-55655 has a CVSS v4.0 base score of 5.0 (CNA self-assessment; NVD's own analysis pending).
How do I remediate CVE-2026-55655?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-55655, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2026-55655

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